Among conventional working vehicles is a wheel loader including an engine, a hydraulic pump connected mechanically to the output shaft of the engine, hydraulic actuators operated with the fluid supplied from the hydraulic pump, a torque converter type automatic transmission connected mechanically to the output shaft of the engine, and a forward/reverse switch (this wheel loader will be referred to as the torque converter vehicle hereunder).
The torque converter vehicle has a modulation function that decelerates the vehicle when the forward/reverse switch is set to the opposite of the current traveling direction of the vehicle. In modulation mode, the gear of the automatic transmission is switched to reverse the rotation direction of the input shaft and that of the output shaft of the torque converter so as to generate the braking force through slippage of the torque converter. This allows the torque converter vehicle to decelerate the vehicle without using hydraulic brakes and to proceed to accelerate in the direction designated by the forward/reverse switch.
Meanwhile, there is an electrically driven cargo handling vehicle including an engine, a generator and a hydraulic pump driven by the engine, a travel device that drives rotatively the front and rear running wheels by means of electrical traveling motors powered electrically by the generator, and a cargo handling device and friction brakes driven by hydraulic pressure from the hydraulic pump. On this cargo handling vehicle, the regenerative braking torque of regenerative braking is allotted as the total braking torque for temporarily stopping the vehicle body in order to switch between forward and reverse traveling in a short time. Where the total braking torque is not fully obtained with the regenerative braking torque alone, the shortage of the torque is supplemented with frictional braking torque (e.g., see Patent Document 1).